As computers become used in more diversified locations and the processing becomes more complex, the frequency and effect of interruptions in the source of power to the computer can cause a situation wherein a substantial amount of work may be lost.
Computers in general are provided with a permanent storage, and with quantities of intermediate or buffer storage, all interfacing with the user mostly through a display. As the work in process proceeds, material is moved from one location to another under direction of the user through an operating system in the computer.
In the event of an interruption of power, the portion of the work in process that has not at that time been placed in the permanent storage is generally lost. Further, in some computers internal systems may be affected by a disorderly termination of operations and some external computer interfaces require formal sign-off instructions.